A few years ago you could be forgiven for thinking virtual reality died a quiet death in the mid 90s, but then the Oculus Rift pulled in a few million dollars on Kickstarter and much more from venture capitalists. Suddenly everyone wants in in this head-mounted display thing, even companies you wouldn’t expect to care. Facebook surprised everyone recently when it bought Oculus VR for $2 billion. Sony is working on its own VR peripheral for the PS4, and now Microsoft might be planning its own version of VR after buying $150 million in patents from a company you’ve probably never heard of.

Microsoft has purchased 81 current and at least 75 in-process patents from a firm called Osterhout Design Group. This company doesn’t make consumer technology, which explains its low profile. Osterhout’s biggest customer is the US government, but the company also has (or rather had) a large cache of VR patents with titles like “Video display modification based on sensor input for a see-through near-to-eye display.”

Osterhout Design Group is already working on a new type of VR product that is covered by different patents not acquired by Microsoft, but what’s Microsoft going to do with its new VR portfolio?The most likely course of action would be to build a VR headset competitor to the Oculus and Sony Project Morpheus. This might be restricted to the Xbox One, or it might be compatible with the PC down the road, much like the Kinect.

If this device is based on the Osterhout patents, it might have a different use case than currently announced VR systems. Most of the Osterhout patents cover semi-transparent display tech that is lighter that a fully-enclosed visor — maybe more augmented reality than virtual reality. Still, many of the patents are general enough that Microsoft could simply be setting itself up to cash in by extracting licensing fees from other companies, much like it does with Android. Whatever Redmond’s plans, they’ve got some catching up to do.